I once read an article questioning the safety and usefulness of the tetanus vaccine. This vaccine is made of the tetanus toxin itself, denatured such that it doesn't cause problems, only induces an immune response. Preparing it requires growing large quantities of the organism,
Clostridium tetani, so components of the bacterial medium are involved in the production process. This is relevant, because some of the problems this anti-tetanus-vaccine article mentioned were anaphylactic shock from the vaccine, and cited several case studies to demonstrate this.
1-4
So is anaphylaxis a real risk of the tetanus shot? Let's look at the data.
These four studies pretty much all say the same thing, with slight variations. The first, by Parish and Oakley, is a case report of a person who experienced an anaphylactic reaction after the second in the two-shot series of tetanus toxoid, though she hadn't reacted at all to the first injection, or to previous injections of diphtheria toxoid, typhoid, or
Staphylococcus toxoid. It didn't seem too serious and she didn't have any breathing problems, but they gave her some adrenaline and the symptoms mostly went away. Everything was better after two days. This person was the only one to experience such a reaction out of 300 others that received the series from the authors.
The second study, by Whittingham, discusses how toxoid is a much safer way to prevent tetanus than the other option at the time, antitoxin serum, because 10-15% of subjects got something called serum sickness (an immune reaction to the serum, not as serious as anaphylaxis, though some got anaphylaxis too). And immunity was better from toxoid. But he reports that, out of more than 61,000 soldiers who got the tetanus toxoid series, 651 (about 1%) had local reactions, 14 (0.023%) had headache and body pains and such lasting up to 8 hours, and 2 (0.0033%) had anaphylaxis. So anaphylaxis occurred in 1 out of 30000. These two cases were fine after adrenaline injections.
The third study, by Cooke, Hamptom, Sherman, and Stull, was another case report of a reaction soon after the second injection of toxoid: the patient had hives, itching, and swelling, but was fine after epinephrine injection.
The fourth, by Cunningham, was a report of a nurse who had had a reaction to a diphtheria toxoid before: hives and malaise. This person had a reaction 3 weeks after the 1st tetanus injection, so it wasn't clear that it was connected at all; she was playing tennis and got hives and irritation. Adrenaline solved it. The second injection was given, along with some adrenaline, and the patient had more problems, but recovered after 24 hours. The author recommends keeping patients under observation for 30 minutes after injection.
So it seems that reactions happened, but didn't seem serious and were pretty rare, based on these studies.
"Anaphylactic reactions following tetanus toxoid injection have also been reported in the medical literature. Fortunately, sensitivity reactions to tetanus toxoid are very rare."5
"Systemic anaphylaxis has been reported following administration of tetanus toxoid also, but this is extremely rare."6
Relevant Component Removed
The other thing
that all these studies talk about is that when the patients mentioned were tested for allergy to components of the vaccine, they all showed reactions to a particular component of the bacterial medium, a kind of peptone (digestion of protein). So it's this component that seemed to be the culprit. Fortunately, it seems that since these reports, steps have been taken to remove this component from production, thus greatly reducing the risk of anaphylaxis:
"From data collected early in the program, it appeared that the proportion of reactions of sensitivity following the injection of these toxoids was at least six times that following the use of toxoids free from these particular peptones.
"As a result of these findings, the procurement and distribution of tetanus toxoid containing Witte or Berna peptones were discontinued. As indicated above, the incidence of reactions of sensitivity has fallen sharply since that time."7
"The production of tetanus toxin on a medium free from peptone has been accomplished with one strain of Cl. tetani. As good, or somewhat better, toxin titers have been obtained as this strain repeatedly yields on peptone-infusion media."8
"Employed on a tremendous scale for military immunization, its initial preparation on the traditional media containing Witte's peptone has had to be modified because of the presence, in that brand of peptone, at any rate, of a substance inducing severe anaphylaxis in certain individuals. Other varieties of peptone are still considered admissible, largely because no serious accidents have thus far been reported following their use."9
"A formula is given for large-scale production of tetanal toxin on a medium initially free from antigenic components."10
"This observation, considered in the light of the experience of Cooke and Whittingham and associates with the sensitizing properties of Witte's and Berna's peptones in toxoids, led to cessation of the use of toxoids containing these peptones with a resultant much lower rate of reactions to tetanus toxoid. In the early immunization toxoids of these types had been used for about 75% of the injections reported and were responsible for 90% of the sensitivity reactions observed."11
"It should be noted, however, that such proteoses were eliminated from all toxoids by 1942."12
So overall, the reaction was rare to begin with, but much rarer after the chief offending component was removed. The original article I mentioned did talk about the peptones, but didn't mention how rare the reaction was to begin with (or how easily treated), and didn't mention that the peptones were removed from vaccines in the future. So I have corrected this misinformation.
Note that this is not a thorough review of the subject; there are other reports of reactions like this, some of which are probably more serious than these four, but I haven't gotten to those reports yet, except insofar as they address these four.
References:
